The home secretary has stressed the need for even greater surveillance powers for government.

In a speech to an Institute for Public Policy Research commission on Wednesday, the home secretary, Jacqui Smith, said the introduction of new laws to monitor modern communications is necessary in order to combat terrorism and serious crime.

The Home Office is already consulting on plans, due to come into effect in 2009, that would require all ISPs to keep the 'who', 'when' and 'where' details of all web, VoIP and messaging traffic for at least 12 months, bringing the UK in line with an EU directive.

Telecoms operators are already required to store similar details of phone calls and text messages for an equivalent length of time.

In her speech, Smith suggested that forthcoming legislation will go further than simply making it a statutory requirement to retain online traffic details for at least 12 months.

She said: "The changes we need to make may require legislation. The safeguards we will want to put in place certainly will. And we may need legislation to test what a solution will look like."

Smith was thought to be referring to plans proposed under the Interception Modernisation Programme (IMP), which are believed to include proposals to siphon details of internet traffic from ISPs and store it in a central government database for at least 12 months.

Lord West of Spithead revealed that the IMP and the Communications Data Bill, due for its first reading in December, are bound together when he told Parliament in July 2008 that more details on the IMP would be available after the draft bill is published this December.

A spokesperson for the Information Commissioner's Office opposed the move towards a centralised database, saying: "It is important to highlight that creating large collections of data is not a risk-free option."

"This not only engages concerns about unwarranted intrusion into the lives of every citizen, it also raises worries about making sure that people's personal information is properly safeguarded, is not misused and can never fall into the wrong hands," said the spokesperson.

Smith said public consultation on any legislation relating to communications retention will begin in the new year.

She added that there are no plans to keep the contents of emails, texts, instant messages or phone calls, and that local authorities will not be given powers to listen in on calls.